This invention relates to roof constructions for buildings and, in particular, to such constructions with wide spans, consisting of three-dimensional lattices or frameworks in which the bars are arranged in clusters in several mutually intersecting planes, the planes being group-wise parallel.
Such frameworks are widely known in planar construction, and increasingly also for domes or gabled roofs or for individual forms extending in several planes. They have been used so far as supports for space-sealing roof elements of the arbitrary type.
The object of the present invention is to exploit solar energy by means of frameworks of the above type. As solar heat is free, the economical efficiency of such utilization practically depends only on the investment in the solar equipment. Accordingly it is important to minimize to the utmost the installation costs of the solar collectors proper and also for the integration of their accessories.
It is already known to arrange solar collectors for solar heating on the surface of slanted (gabled or single-slant) roofs resting on conventional lumber construction, and to integrate them into the roofing material over said lumber. However, steep gabled roofs sloping advantageously with respect to solar irradiation are impossible for wide-span buildings (arenas, plants, etc.). Therefore, flat roofs or at least truncated domes or low-height barrel roofs are used for such wide-span buildings. As regards flat roofs, it has been possible so far to erect solar collectors at a slant above the roofing only by using special mounting means for the purpose of receiving a maximum of solar heat. In such cases, therefore, high costs are added to the supporting roof construction and roofing by the costly mounting means for the solar collectors. To the extent that the building seen in top view does not face toward the sun at high noon (toward the south in the northern hemisphere), such mounting means require rotation with respect to the axes of the building in order to achieve the most advantageous position of the solar collectors for heat absorption. While theoretically quite simple, this does cost a lot of money in practice.